<?php
    header("content-type:text/html;charset=utf8");
    $username = $_POST['username'];
    $goodsid = $_POST['goodsid'];
    $con = mysqli_connect("localhost","root","root","user");
    mysqli_query($con,"set names utf8");
    $res = mysqli_query($con,"select * from history where username='$username' and goodsid=$goodsid");
    $row = mysqli_fetch_assoc($res);
    if($row){
        mysqli_query($con,"delete from history where id=".$row['id']);
    }
    mysqli_query($con,"insert history(username,goodsid) values('$username',$goodsid)");

?>
